EXHIBIT 32.1


                             CERTIFICATE PURSUANT TO
                               18 U.S.C. ss. 1350,
                             AS ADOPTED PURSUANT TO
                    ss. 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection  with the Annual  Report on Form 10-K of Mission West  Properties,
Inc.  (the  "Company")  for the year ended  December  31, 2007 as filed with the
Securities and Exchange  Commission on the date hereof (the  "Report"),  each of
Carl E. Berg,  Chairman  of the Board and Chief  Executive  Officer,  Raymond V.
Marino, President and Chief Operating Officer, and Wayne N. Pham, Vice President
of Finance and Controller of the Company, hereby certify,  pursuant to 18 U.S.C.
ss. 1350, as adopted pursuant to ss. 906 of the  Sarbanes-Oxley  Act of 2002, to
the best of his knowledge, that:

     (1) The Report fully  complies  with the  requirements  of Section 13(a) or
15(d) of the Securities Exchange Act of 1934, as amended; and

     (2)  The  information  contained  in the  Report  fairly  presents,  in all
material  respects,  the  financial  condition  and result of  operations of the
Company for the periods included in the Report.

/s/ Carl E. Berg
- -------------------------------------------
Carl E. Berg
Chairman of the Board and Chief Executive Officer
March 13, 2008

/s/ Raymond V. Marino
- -------------------------------------------
Raymond V. Marino
President and Chief Operating Officer
March 13, 2008

/s/ Wayne N. Pham
- -------------------------------------------
Wayne N. Pham
Vice President of Finance and Controller
March 13, 2008


This  certification   accompanies  this  Report  pursuant  to  ss.  906  of  the
Sarbanes-Oxley  Act of 2002 and shall not,  except to the extent required by the
Sarbanes-Oxley  Act of 2002,  or  otherwise  required,  be  deemed  filed by the
Company  for  purposes  of ss. 18 of the  Securities  Exchange  Act of 1934,  as
amended.

A signed  original of this  written  statement  required by section 906 has been
provided to the Company and will be retained by the Company and furnished to the
Securities and Exchange Commission or its staff upon request.